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Thread: 2D ARRAY PROBLEM

  1. #1
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    Default 2D ARRAY PROBLEM

    I have a 2D array called box.

    int[][] box = new int [2][3];

    Its has elements as follows:

    box [0][0] = 1;
    box [0][1] = 2;
    box [0][2] = 3;
    box [1][0] = 1;
    box [1][1] = 2;
    box [1][2] = 3;

    I want to end up after coding with elements in the array as follows:
    box [0][0] = 2;
    box [0][1] = 3;
    box [0][2] = 3;
    box [1][0] = 2;
    box [1][1] = 3;
    box [1][2] = 3;
    i.e All elements in each column has had its values
    replaced by values from its immediate right hand column

    I have tried :
    for (int j = 0; j < box.length - 1; j++)
      for (int i = 0; i < box.length - 1; i++)
       box[i][j] = box[i] [j + 1];
    but no joy. Any thoughts please??


  2. #2
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    Default Re: 2D ARRAY PROBLEM

    Quote Originally Posted by av8 View Post
    but no joy.
    That provides zero information. Presumably your code didn't work. Since there is a gazillion reasons why it didn't work we have no idea what your problem is. If you provide details it will help others help you.

    Hint: a 2D array is simply a 1D array of 1D arrays.
    int[][] matrix = {{1,2,3}, {4,5,6}, {7,8,9}};
    for(int outer = 0; outer < matrix.length; outer++) {
        int[] temp = matrix[outer];
        for(int inner = 0; inner < temp.length; inner++) {
            System.out.print(temp[inner] + " ");
        }
        System.out.println();
    }
    So you can concentrate on 1 dimension instead of 2.

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    Default Re: 2D ARRAY PROBLEM

    for (int j = 0; j < 2; j++)
    for (int i = 0; i < 1; i++)
    box[i][j] = box[i] [j + 1];

    The above code is now working correctly. Thanks for commenting Junky.

    kind regards av8

  4. #4
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    Default Re: 2D ARRAY PROBLEM

    Do not hard code values like that. It will not work for a 2D array of any other size.

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